Envelope wall with two continuous ledges for positioning and supporting aperture mask



Oct. 1, 1968 w. H. NICKLAS 3,404,302

ENVELOPE WALL WITH TWO CONTINUOUS LEDGES FOR POSITIONING AND SUPPORTINGAPERTURE MASK Filed June '21, 1967 unu uuu INVENTORI w LLIAM H. NICKLAS,

HIS ATTORNEY.

United States Patent 3,404,302 ENVELOPE WALL WITH TWO CONTINUOUS LEDGESFOR POSITIONING AND SUPPORT- ING APERTURE MASK William H. Nicklas, NorthSyracuse, N.Y., assignor to General Electric Company, a corporation ofNew York Filed June 21, 1967, Ser. No. 647,699 3 Claims. (Cl. 31385)ABSTRACT OF THE DISCLOSURE A support arrangement for an aperture maskincluding a continuous self-stiffened periphery and a number of integralmale or female registry points thereabout. The support arrangementincludes a pair of continuous spaced peripheral ledges molded from theinterior surface of the tube envelope, one of which ledges includes anumber of male or female registry points molded therein. The aperturemask, as supported in the tube, is disposed so that the peripherythereis is in juxtaposition with said one ledge and the registry pointsare aligned. Tensioning means, in the form of elongated wire springs,span the ledges to firmly restrain the aperture mask from movement.

Background of invention This invention relates to aperture masks forcathoderay tubes and, more particularly, to improved means forsupporting aperture masks in color television tubes.

The display screen for a color television tube is ordinarily positionedadjacent the viewing face of the tube and usualy consists ofphosphorescent color emitting material. In order to properly directelectron beams from a source at the rear of the tube so that onlycertain electron beams strike predetermined color emitting areas on thedisplay screen, an aperture mask is normally positioned adjacent thedisplay screen. The aperture mask comprises a perforated sheet ofmaterial having apertures strategically positioned so that only thedesired electron beams are able to pass therethrough. The aperture maskusually is supported within the tube by a supporting arrangement whichspans the space between the mask periphery and the inner surface of thetube. In order to shield stray electron beams from escaping around theperiphery of the mask, some known devices employ a beam shield extendingaround the mask periphery. Other known devices have eliminated the beamshield by extending the mask to engage directly the inner surface of thetube. In these devices various supporting and mounting arrangements havebeen provided to fix the mask to the tube surface.

These prior art support arrangements for such aperture masks havegenerally proven to be effective. However, with the production of largevolumes of color television tubes, tube manufacturers are alwaysdesirous of uncovering new ways of manufacturing components, such asaperture mask supports, which will result in reduced costs, while eitherretaining or improving the characteristics and functions of the priorart devices.

Summary of invention It is therefore an object of this invention toprovide a simple and inexpensive support arrangement for the aperturemask of a color television tube.

It is another object of this invention to provide an improved aperturemask for a color television tube and supporting arrangement thereforwhich shields stray electron beams from escaping around the peripherythereof.

In accordance with one aspect of the invention, I provide a cathode raytube including an envelope therefor,

and a pair of continuous peripheral ledges molded from the interiorsurface of the tube envelope. An aperture mask is provided having aperipheral surface formed to be self-stiffening and includes a number ofintegral registry points along the self-stiffened periphery that matewith registry points molded in one of the ledges. After the aperturemask is positioned so that the self-stiffened periphery bears upon thisledge, and after the registry points are aligned, a number of springswhich span the ledges are periodicaly positioned thereabout so as tofirmly trap the aperture mask against the adjacent ledge. Thecooperation of the continuous ledges and the aperture mask serves alsoto effectively shield any electron beams which might escape around theperiphery of the aperture mask.

Detailed description Other objects and advantages of the invention maybetter be understood by reference to the following description taken inconnection with the accompanying drawings in which:

FIGURE 1 is a view of the support arrangement of the invention in acathode-ray tube having a portion of the envelope broken away;

FIGURE 2 is a perspective view of the aperture mask of the presentinvention; and

FIGURE 3 is an enlarged view of a portion of the support arrangementtaken along line 3-3 of FIGURE 1.

FIGURE 1 shows a television tube comprising an envelope 1 having afunnel section 2 and a face panel section 3. The face panel section andthe funnel section are joined together by means of a peripheral fritmember 4. The funnel section 2 includes a flared portion 5 and a neckportion 6 wherein is disposed a source 7 for generating electron beams.The face panel section 3 includes a face plate portion 8 and a skirtportion 9. A phosphorescent color emitting display screen 10 is disposedadjacent the interior surface of the face plate portion 8 of the facepanel section 3.

An aperture mask 11, best seen in FIGURE 2, is provided between thesource of electron beams 7 and the display screen 10. The aperture mask11 comprises a perforated sheet of metal having apertures 12strategically positioned so that only certain electron beams pass therethrough and onto the display screen 10. The aperture mask 11 includes anouter peripheral surface 13 which is non-perforated and which is formedto be self-stiffening. By self-stiffening, it is meant that theperiphery '13 is so formed that it attains a strength and rigiditybeyond what it normally may possess. In this particular embodiment themask 11 is self-stiffened by deforming the periphery 13 in somewhatsinusoidal fashion. Such deformation results in a channel 14 of greaterrigidity being formed close to the perforated portion of the mask 11, afiat portion 16 extending from the channel 14 and a downturned flangeportion 17. Note that the non-perforated nature of the periphery 13allows it to serve as a shield to prevent overscanned electrons whichstrike the edge of the mask 11 from leaking through to the screen.

The aperture mask 11 is mounted in the envelope 1 through theutilization of applicants novel support arrangement. The skirt portion 9of the faceplate section 8 includes a first molded-in continuous annularledge 18. The ledge is adapted to receive in juxtaposition the flatportion 16 of the peripheral surface 13 of the aperture mask 11 formounting purposes. The funnel section 2 also includes anchoring means 24comprising, preferably, a second molded-in continuous peripheral ledge19. The anchoring'means 24 may also comprise a number of protuberancesor anchor members spaced annularly around the funnel section, ifdesired, As is shown in FIGURE 3, the first ledge 18 also includes anumber of molded-in registry points compriisng conical lands or holes orgrooves to mate with registry points comprising abutment members formedinto the fiat portion 16 of the mask periphery 13 so that the aperturemask 11 may be properly aligned within the envelope 1. The aperture mask11 must be properly aligned because precise positioning of the apertures12 in the mask 11 is essential for proper direction of the electronbeams onto the display screen 10. After the aperture mask 11 has beenpositioned against the first ledge 18 and the registry points 15, 20have been properly aligned, a plurality of elongated wire springs 21 orthe like are inserted to span the space between the ledge 18 and 19, inthe preferred form, to restain the aperture mask 11 from movement. Oneend 22 of each spring 21 rests against the funnel ledge 19 while theother end 23 of each spring 21 exerts an outward force against the maskperiphery 13, thereby trapping the mask 11 against the first ledge 18and restraining it from movement. In addition, the springs 21 provide anelectrical connection between a conductive coating of the funnel section2 and the mask 11.

The continuous molded-in ledge 18, by virtue of its continuousengagement with the periphery 13 of the aperture mask 11, serves toeffectively shield any electron beams which might escape around theperiphery of the aperture mask, thereby eliminating the necessity of aseparate beam shield for such purpose.

Groove portions may be additionally provided in the second ledge and inthe periphery of the aperture mask to firmly index the wire springs.

While the invention has been described with specificity, it is the aimof the appended claims to cover all such equivalent variations as comewithin the true spirit and scope of the foregoing disclosure.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a cathode ray tube including a glass envelope and an aperture maskformed with a self-stilfened outer periphery, an arrangement forsupporting said aperture mask within said envelope comprising:

(a) one continuous peripheral ledge molded from said envelope anddisposed along the inside surface thereof;

(b) anchoring means disposed along the inside surface of said envelopeand spaced from said one ledge, said anchoring means comprising a secondcontinuous peripheral ledge molded from said envelope; and

(c) a number of tension springs which may he positioned to span thespace between said one ledge and said anchoring means so as to trap theperiphery of said aperture mask against said one ledge to provide anelectron-impermeable seal when the periphery of said aperture mask isfirst placed in juxtaposition and in continuous engagement with said oneledge.

2. The supporting arrangement as recited in claim 1 wherein saidself-stiffened outer periphery of said aperture mask is provided withintegral spaced registry points and said one ledge is provided withintegral spaced registry points, and whereby said registry points arealigned when said periphery of said aperture mask is placed injuxtaposition with said one ledge.

3. In combination, for a television cathode ray tube including a glassenvelope:

(a) an aperture mask comprising a perforated portion surrounded by acontinuous self-stiffened non-perforated peripheral portion;

(b) one continuous peripheral ledge molded from said envelope anddisposed along the inside surface thereof;

(c) anchoring means disposed along the inside surface of said envelopeand spaced from said one ledge, said anchoring means comprising a secondcontinuous peripheral ledge molded from said envelope; and

(d) a number of tension springs which may be positioned to span thespace between said one ledge and said anchoring means so as to trap theperiphery of said aperture mask against said one ledge when theperiphery of said aperture mask is placed in juxtaposition and incontinuous engagement with said one ledge,

References Cited UNITED STATES PATENTS 2,690,518 9/1954 Fyler et a1. 3132,824,989 2/ 1958 Christolferson 313-85 2,897,392 7/1959 Fiore 313-852,906,904 9/1959 Woughter et al. 313-85 2,961,560 11/1960 Fyler 313-643,005,921 10/ 1961 Godfrey 313-85 3,038,096 6/1962 Knochel et al.313--85 ROBERT SEGAL, Primary Examiner.

